Telescoping concave projection screen

ABSTRACT

A projection system using an image forming light transmitting globe over a light source to project the image onto a telescoping concave projection screen centered with respect to the light source and preferably formed in three sections which telescope upwardly when not in use to a position adjacent the ceiling of a room.

United States Patent 1 1 3,632,185

[72] inventor Howard Allen Meanor 2,477,027 7/1949 Wenberg 35/43 5317 EastBoulevardN.W.,Canton,0hio 2,753,818 7/1956 Green 35o/12sx A IN $12 FOREIGN PATENTS PP- 1 1,037,721 8/1958 Germany 350/125 [221 17,1969 188,164 11/1966 U.S.S.R. /425 Patented Jan. 4, 1972 Primary Examiner-Janis R. Prince Assistant Examiner-Joseph W. Roskos [54] TELESCOPING CONCAVE PROJECTION SCREEN wi] i P Hi k 10 Claims, 4 Drawing Figs. [52] US. Cl ABSTRACT: A projection system using an image forming [5 I] I t 3 21/58 light transmitting globe over a light source to project the i 350/ image onto a telescoping concave projection screen centered l 35208 with respect to the light source and preferably fonned in three sections which telescope upwardly when not'in use to a posi- 5 References Cited tion adjacent the ceiling of a room.

UNITED STATES PATENTS 2,273,074 2/1942 Waller 350/125 PATENTED m 4m SHEET 1 UF 2 INVENTER. HOW/IEO A. Men/v02 A r'rokweY' PATENTED JAN M972 8.632.185

SHEET 2 [IF 2 l N V EN TER. #0 men A. Men/v02 A TTOENY TELESCOPING CONCAVE PROJECTION SCREEN BACKGROUND OF THE INVENTION The present invention relates to a planetarium system of the type wherein an image is projected onto a concave projection screen centered above the image projector. The prior art has used such a projection system, but the projection screens that have been used therewith are for the most part fixed structures which make the room in which they are installed generally unusable for any other purpose.

An object of the present invention is the provision of a new and improved dome-shaped projection screen made in telescoping pieces which will collapse against the ceiling of a room in such manner as not to interfere with people walking underneath, even when installed in a room having a ceiling as low as feet.

A further object of the present invention is the provision of a three-piece telescoping screen of the above described type having a center section which does not become canted.

Another object of the present invention is the provision of a screen of the above-described type, the sections of which are made from smaller pieces which fit together to form surfaces of revolution, and which pieces reinforce each other when fastened together.

A still further object of the present invention is the provision of ventilation means in the top of a screen of the abovedescribed type which does not cast objectionable shadows.

Further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description and drawings which are a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view in elevation showing one embodiment of the invention;

FIG. 2 is an elevational view in section of the embodiment shown in FIG. 1 showing the screen in its collapsed condition;

FIG. 3 is a fragmentary sectional view in elevation of another embodiment of the invention; and

FIG. 4 is a fragmentary sectional view in elevation of still another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of telescoping screen shown in FIGS. 1 and 2 of the drawings generally comprises an upper domeshaped section 10, a middle telescoping section 12, and a lower telescoping section 14. Each section has an inner surface which preferably is a surface of revolution, and is preferably formed by pieces that are connected together to form the section. The embodiment shown in FIGS. 1 and 2 has sections which are formed by flanged pieces the flanges 16 of which are bolted together. The pieces can be made of any suitable material, and in the embodiment shown in the drawings, are made from fiber glass impregnated with a thermosetting polyester resin. The upper end of each piece of the dome-shaped section 10 has a flange 18 which when the pieces are bolted together, form a ring surrounding a vent opening. One of the difi'iculties with prior art screens is that there is no ventilation within the dome. In the present embodiment, a perforated piece of sheet material, as for example aluminum, extends across the opening formed by the flanges 18, and is suitably affixedinto position.

The upper dome-shaped section 10 is supported from the ceiling of the room in which it is installed by three spaced rods the lower ends of which are bolted to connecting pairs of the flanges 16. The upper ends of the rods 20 may be fastened to the ceiling structure in any suitable manner, and as shown in the drawing are bolted to channel irons which are connected together at 120 angles, and are centered over the upper dome section 10. One of the channel irons extends 90 to the closest wall of the room.

The inner surface of the middle section 12, shown in the drawing, has a lower reflective surface portion that is spherically shaped and an upper portion which overlaps the side edge of the bottom of the dome section 10. The bottom edge of the dome section 10 may cast a shadow on the section 12 in some instances, and in order that this will be minimized, the inside edge of the surface of the dome section 10 is tapered toward its outside surface. The radius of the middle section 12 is, therefore, equal to the radius of the inside surface of the dome section 10, plus the thickness of the upper dome section 10. The middle section 12 is guided for vertical movement in a manner to prevent canting relative to the upper dome section 10 by three rods 22 which are rigidly fastened to alternate pairs of the flanges 16 in a vertical and fixed manner. The upper end of the rods 22 are fixed to horizontal plates 24 by a pair of clamping nuts 26, and the other end of the plates 24 carry a tubular section 28 each of which fits around one of the rods 20 and establish a sliding guide therewith.

The inner surface of the lower section 14, likewise has a lower reflective surface portion that is spherically shaped and an upper portion which overlaps the outside edge of the middle section 12. The radius of the section 14 is, therefore, equal to the radius of the inside surface of section 12 plus the thickness of section 12. The lower inside surface of section 12 is preferably tapered toward its outside surface. Section 14 is adapted to be raised by 3 pulleys 32, the lower ends of which are fixed to alternate pairs of the flanges 16. The cables 30 extend directly upward and around pulleys 32, then laterally to a position adjacent the wall of the room, and downwardly over three closely spaced pulleys 34. The center cable extends downwardly to a winch 36 located at a convenient height above the floor of the room, and the other two cables 30 are fastened to the center cable a short distance below the pulleys 34, so that the cables 30 are foreshortened equally when the winch 36 is actuated.

Actuation of the winch 34 causes the cables to be foreshortened by equal amounts to raise the lower section and maintain it in a horizontal position. The lower edge of the lower section 14 is provided with three equally spaced abutments 38 which extend radially inwardly by a distance sufficient to engage the bottom edge of the middle section 12. Upward movement of the lower section 14, therefore, causes the abutments 38 to engage the bottom edge of the middle section 12 and carry it upwardly in a horizontal position. The three sections l0, l2 and 14 have approximately equal depths, and it will be seen that a dome 12 feet in diameter, will in its telescoped position, project downwardly into a room having a 10 foot ceiling no more than approximately 3 feet to leave 7 foot clearance.

The embodiment shown in FIG. 3 is generally similar to the embodiment shown in FIGS. 1 and 2 excepting that the top of the upper dome section is vented positively by a fan in such manner as to avoid shadows. Those portions of the embodiment shown in FIG. 3, which are similar to corresponding portions of the embodiment shown in FIGS. 1 and 2, are designated by a like reference numeral characterized further in that a suffix a is affixed thereto. In the embodiment shown in FIG. 3, a generally dome-shaped shield 40, that is larger in diameter than the opening formed by the flanges 18, is spaced downwardly from the inside surface of the dome section 10 by an inch or more. The space between the shield and the bottom surface of the dome section, therefore, provides an opening through which air can be drawn. Light bulbs 42 are positioned upwardly from the shield so as to cast a reflected light from the top surface of the shield which illuminates the overlapped area of the bottom surface of the dome section 10. A shield 44 is preferably positioned inside of the lights 42 to prevent direct rays therefrom from shining out of the opening .between the shield 40 and the bottom surface of the dome 10.

A motor driven fan 46 is positioned upwardly of the lights 42 to pull air out of the top of the screen. The embodiment shown in FIG. 3 also preferably includes a cove 48 around the inside lower edge of the lower section 14 having lights 50 therein which can be dimmed by the dimmer switch 52. The lights 42 are preferably tied in with the dimmer switch 52 so that the illumination of the dome can be increased or decreased in intensity to simulate sunrise andsunset, etc. The top surface of the cove 48 can provide the abutment which raises and lowers the middle section 12.

The embodiment shown in FIG. 4 is generally similar to the embodiment shown in FIGS. 1 and 2 excepting that the inside reflective surface of the middle and lower sections 12 and 14 are conically shaped instead of spherically shaped. Those portions of the embodiment shown in FIG. 4 which correspond to similar portions of the embodiment shown in FIGS. 1 and 2 are designated by a like reference numeral characterized further in that a suffix b" is affixed thereto. In the embodiment shown in FIG. 4, a normal to the center of the reflective surfaces of the conically shaped sections 12b and 14b intersect at a point a short distance below the plane of the bottom edge of section 14b. The image on the screen, therefore, will be sharp and clear without unwanted lines or fuzziness. Also according to the invention, the screens can be provided with suitable indicia 54 to indicate azimuth and the points of the compass, and to allow their removal from the image producing surface. By so doing, the image producing surface can be rotated to show various effects relative to these indicia.

While the invention has been described in considerable detail, I do not wish to be limited to the particular embodiments shown and described, and it is my intention to cover hereby all novel adaptations, modifications, and arrangements thereof which come within the practice of those skilled in the art to which the invention relates.

I claim:

1. A screen for projected images comprising: upper, middle, and lower rigid shell sections each having inner and outer generally parallel surfaces of revolution with the normal to the center of each section passing generally through the same point, said normal of said middle section being approximately equal in length to the normal of the outside of said upper section, and the normal of said lower section being approximately equal in length to the normal to the outside of said middle section, the upper portion of said inner surface of said middle section being adapted to engage the lower portion of said outer surface of said upper section, and the upper portion of said inner surface of said lower section being adapted to engage the lower portion of said outer surface of said middle section, means for supporting said upper section with its inner surface of revolution facing downwardly, abutment means on said lower shell section for engaging and raising said middle section, and means for raising and lowering said lower section.

2. The screen of claim 1 wherein: said means for supporting said upper section includes vertically extending supports, and said middle section is guided for vertical movement from said vertically extending supports.

3. The screen of claim 2 wherein said telescoping sections have generally conically shaped inner surfaces.

4. The screen of claim 1 including: a cove around the inside lower edge of said lower section having lights therein.

5. The screen of claim 4 wherein the center of said upper section has a ventilation opening therethrough, and a light reflective surface spaced from said upper section beneath said ventilation opening.

6. The screen of claim 5 having light means positioned upwardly from said opening, and means for dimming said light means simultaneously with said lights in said cove.

7. The screen of claim 1 wherein said middle and lower sections are in flanged pieces with the flange extending outwardly and connected together.

8. The screen of claim 1 wherein the inside lower edges of said middle and upper shell sections are tapered.

9. A telescoping screen for receiving a projected image cast by an image spaced around a light source, said screen comprising: a upper rigid shell section having an inner spherical surface adapted to be centered over a point where the light source is to be situated and an outside spherical surface adjacent its lower edge, and a first rigid telescoping shell section having an inside spherical surface of approximately the same radius as said outside spherical surface so as to engage the outside bottom surface of said upper shell section, and means for raising and lowering said first telescoping section.

10. The telescoping screen of claim 9 including a second rigid telescoping shell section having an inside spherical surface of approximately the same radius as said outside surface of said first telescoping section and adapted to engage the outside bottom edge of said first telescoping shell section, said means for raising said first telescoping section comprising uniformly spaced abutments on said second telescoping section for engaging the bottom edge of said first telescoping section after predetermined vertical movement of said second section, and means for raising and lowering said second telescoping section. 

1. A screen for projected images comprising: upper, middle, and lower rigid shell sections each having inner and outer generally parallel surfaces of revolution with the normal to the center of each section passing generally through the same point, said normal of said middle section being approximately equal in length to the normal of the outside of said upper section, and the normal of said lower section being approximately equal in length to the normal to the outside of said middle section, the upper portion of said inner surface of said middle section being adapted to engage the lower portion of said outer surface of said upper section, and the upper portion of said inner surface of said lower section being adapted to engage the lower portion of said outer surface of said middle section, means for supporting said upper section with its inner surface of revolution facing downwardly, abutment means on said lower shell section for engaging and raising said middle section, and means for raising and lowering said lower section.
 2. The screen of claim 1 wherein: said means for supporting said upper section includes vertically extending supports, and said middle section is guidEd for vertical movement from said vertically extending supports.
 3. The screen of claim 2 wherein said telescoping sections have generally conically shaped inner surfaces.
 4. The screen of claim 1 including: a cove around the inside lower edge of said lower section having lights therein.
 5. The screen of claim 4 wherein the center of said upper section has a ventilation opening therethrough, and a light reflective surface spaced from said upper section beneath said ventilation opening.
 6. The screen of claim 5 having light means positioned upwardly from said opening, and means for dimming said light means simultaneously with said lights in said cove.
 7. The screen of claim 1 wherein said middle and lower sections are in flanged pieces with the flange extending outwardly and connected together.
 8. The screen of claim 1 wherein the inside lower edges of said middle and upper shell sections are tapered.
 9. A telescoping screen for receiving a projected image cast by an image spaced around a light source, said screen comprising: a upper rigid shell section having an inner spherical surface adapted to be centered over a point where the light source is to be situated and an outside spherical surface adjacent its lower edge, and a first rigid telescoping shell section having an inside spherical surface of approximately the same radius as said outside spherical surface so as to engage the outside bottom surface of said upper shell section, and means for raising and lowering said first telescoping section.
 10. The telescoping screen of claim 9 including a second rigid telescoping shell section having an inside spherical surface of approximately the same radius as said outside surface of said first telescoping section and adapted to engage the outside bottom edge of said first telescoping shell section, said means for raising said first telescoping section comprising uniformly spaced abutments on said second telescoping section for engaging the bottom edge of said first telescoping section after predetermined vertical movement of said second section, and means for raising and lowering said second telescoping section. 